The present invention relates to a golf club head, more particularly to a face support structure suitable for a large-sized hollow head capable of improving rebound performance.
In recent years, in order to improve the rebound performance of golf club heads, various devices were made. In large-sized hollow wood-type club heads in particular, the mainstream tendency to decrease the thickness of the face portion partially or wholly. Such a, technique is widely employed together with light-weight tough metal materials such as titanium alloys. As a result, in the face portion, the thinning of the material thickness accelerated. On the other hand, wood-type clubs have tended towards a large-sized head. Thus other portions such as the sole portion, side portion and especially the crown portion, are also formed with reduced thicknesses. As the face portion is thin, the deflection at impact is increased and thereby the restitution coefficient is increased to improve the rebound performance.
In order to further improve the rebound performance, the inventors made a study on the relationship between the restitution coefficient and the deflection, and it was found that the rigidity of the part supporting the face portion, namely, the front end zones of the crown portion and sole portion largely affects the rebound performance. If the rigidity in such zones is excessively increased, the deflection decreases and the restitution coefficient is accordingly decreased. On the contrary, if the rigidity is excessively decreased, the deflection may be increased, but the restitution coefficient is again decreased. Further, as the strength decreases, the durability is greatly decreased. But then it was discovered that both the restitution coefficient and durability can be improved by gradually changing the rigidity in the front end zones in a special manner.